ESP works perfectly fine. It has everything a pirate needs, such as X marks the spot ESP and treasure ESP. These save a lot of time so you can pretty much speedrun your plundering. I haven't noticed any issues apart from visuals not being very fluid, it might appear a little shakey when you are moving your mouse but you get used to it. Prediction visuals are very accurate as well and I 100% recommend using them, they are godsent.
Aimbot is pretty solid with gunpowder weapons but it's lacking when it comes to cannons so I suggest using prediction markers when you're on a cannon, I assure you won't miss.
From my own experience in Arena and Adventure I didn't encounter any crashes or any significant FPS drops.
This is where this software really shines for me, it gives you information on how many holes your or other ships have and whether you are sinking or not. You can take this to your adventage in Arena and prey on the weak ships to finish them off easily.